
Majuba |

Lord can be a fairly generic term for nobility. I believe the heads of each of Sandpoint's four founding families would probably be referred to as Lord or Lady - Lady Ameiko Kaijitsu for instance.
"His/Your Lordship" is just a way of referring to someone by their title, similar to "His Royal Majesty". The suffix -ship is occasionally used to make a title for almost any position, usually in jest. Good examples escape me at the moment.

robin |
Historically , a lord denotes appartenance to nobility .
When someone didn't have himself a title like a knight or a baron he was a lord . you could then refer him as 'LORD WHOEVER' or when you were speaking directly to him as 'Your Lordship'
When people where insecure about your status but wanted to avoid offense , they began to call people 'your lordship' . So in times , even gentry began to be called so. The appelation was in this way much trivialized
Nowadays , even important merchants are called Lord even if they don't belong to any traditional nobility. Interestingly 'LORD ' stays more precise than lordship even if there are some abuse .